1. Field of the Invention
The invention relates to a wheel chair comprising at least two rear wheels, at least one front wheel, a supporting frame, a seat assembly, simply called xe2x80x9cseatxe2x80x9d hereinafter and in the claims, and a backrest assembly, simply called xe2x80x9cbackrestxe2x80x9d hereinafter and in the claims.
2. Description of the Related Art
A wheel chair of this kind is known from Dutch patent No. 1001164 (Revab BV). The supporting frame of the prior art wheel chair consists of tubular sections, whilst the seat is built up of a seat cushion which is positioned on a seat edge, a flap and a supporting strap. When the supporting strap is fully tightened, the flap is positioned approximately level with the seat edge, and in effect a user does not experience a seat angle. When the supporting strap is adjusted less tight, the seat cushion sinks slightly along with the flap, as a result of which a relatively larger angle of inclination of the seat is obtained. The prior art backrest consists of a backrest cushion, deformation of which can be adjusted individually for each user through adjustment of the straps present therebehind.
One objection of the wheel chair as known from the aforesaid Dutch patent publication is that it does offer an disabled person a possibility to slightly adjust the seat, as regards the angle of inclination thereof, to his or her individual requirements, to be sure, but that it has become apparent in practice that this enables an acceptable seating position only in passive condition, that is, at rest, when the user is for example eating, writing or reading. In active condition, when the user is driving, the prior art wheel chair does not enable an acceptable seating position from an ergonomic point of view.
The object of the invention is to provide a wheel chair which creates an optimum seating position for a user, both at rest and while driving.
In order to accomplish that objective, a wheel chair of the kind referred to in the introduction is characterized in that the seat can be moved from a sitting position to a driving position, and vice versa, wherein the center of gravity of a user""s body is moved parallel to the direction of movement of the wheel chair.
The invention will now be explained in more detail with reference to illustrations of a preferred variant of the invention which are shown in a drawings, wherein: